IRFU chiefs have given their blessing to Andy Farrell to join up with the Lions in South Africa after Ireland's July Tests.
Ireland play Japan on July 3 and USA on July 7, and head coach Farrell will then hook up with Warren Gatland 's squad ahead of the three Lions tests.
Gatland had wanted Farrell on board for a third Lions tour in succession but due to uncertainty over Ireland's planned summer tour to Fiji, the former defence coach was unable to commit.
But IRFU performance director David Nucifora said the green light has been given to the 46-year-old to head out after the USA fixture.
The first Lions Test against the Springboks is not until July 21 in Cape Town and, with Ireland paired with the reigning world champions in the next World Cup, Farrell will feel it makes sense for him to be a part of the Lions set-up.
"Absolutely, it's something we have been in discussion for a long time around how that would all work, whether the tours were on or off," said Nucifora.
"We were always open to the idea that after the tour was finished, if we had a tour, that Andy would go over and join them. We were always happy to do that, Warren was always happy to have Andy there.
"I suppose the way it panned out he's got the ability to be there a little earlier. It's good for Andy, it's good for our players that are on the Lions tour.
"Those things are only a positive, aren't they?"
